In the treatment of aortic diseases (for example, aortic aneurysm or aortic dissection), artificial blood vessel replacement for replacing an affected blood vessel with an artificial blood vessel has been conventionally performed. However, since thoracotomy is required for this treatment, there have been problems that a burden (invasion) on a patient is high and long hospitalization is required. Considering such problems, treatment using a stent graft (stent graft implantation) has been widely used instead of the artificial blood vessel replacement. According to the treatment, a stent graft is encased in a catheter with a small diameter and introduced to an area with aneurysm, and then, the encased stent graft is released from the catheter and expanded, to be placed in an area (affected part) having aneurysm or dissection. Thus, according to the treatment using a stent graft, only a small area is cut in the operation and thoracotomy is not required so that it is a treatment method less invasive than the artificial blood vessel replacement.
For the treatment using a stent graft in an even less invasive manner, it is desirable to decrease a diameter of catheter. For this, it is necessary to use a thin and flexible stent graft base (artificial blood vessel part) to reduce a volume of a stent graft.
For the purpose of solving the above problem, Patent Literature 1 discloses a base fabric for a stent graft which comprises on at least one surface thereof a fiber with a cross-sectional shape which outermost layer has a side approximately parallel to the outermost layer surface, wherein the woven fabric has a yarn density of 150 strands/2.54 cm or more in both longitudinal direction and lateral direction, and a thickness of 1 to 90 μm. The base fabric for a stent graft having such constitutions has thinness, high strength, low permeability and flexibility, and can be inserted into a smaller catheter.
Further, Patent Literature 2 discloses a graft containing a graft fabric which contains a plurality of threads of 5 to 50 denier. It discloses that the graft with such constitution can be encased in an intravascular delivery system with an outer diameter of about 0.06 to 0.27 inch (about 1.52 to 6.8 mm).